Roof antennas of motor vehicles are usually developed as rod antennas and have an antenna holder fastened to the roof of the motor vehicle, in which the rod antenna itself is applied in a fixed or detachable manner. Known antenna holders, such as the antenna holder of an antenna system described in German Patent Application No. DE 102 33 065, as a rule have a broadened base part situated on the inside of the motor vehicle between the inside and the underside of the roof and the roof lining, as well as an anchor connected in one piece with the base, and the anchoring part projecting beyond the base, whose outer cross section is smaller than the opening cross section of the opening, so that it is able to be put through the opening from the inside, during the assembly of the holder. The anchoring part usually has an outer thread, onto which a fastening nut or lock nut may be screwed from the outside after it has passed through the opening, in order to fix the base lying against the roof from the inside, and firmly to clamp the roof between the base and the nut.
In these known antenna holders, it is regarded as disadvantageous that they have to be delivered for assembly in the form of two separate parts, the base and the fastening nut or lock nut, which not only makes difficult the logistics and handling before assembly, but also prolongs the time required for the assembly.